Compass on COVID: What test for whom and when—lab leaders talk

November 2020—Testing saliva, stocking up, and expanding capacity were top of mind when members of the Compass Group convened by Zoom on Sept. 1 for a second COVID-19-related call with CAP TODAY publisher Bob McGonnagle. Antigen testing, too, came up, and the question to answer there, said Susan Fuhrman, MD, of OhioHealth, is why the test is performed and what will be done with the result.

That and more—testing for patients undergoing treatment for cancer, flu season—were up for discussion. Others on the call were Greg Sossaman, MD, of Ochsner; Lauren Anthony, MD, and Heather Dawson of Allina; Sarah Province and Julie Hess of AdventHealth; James Crawford, MD, PhD, of Northwell; Stan Schofield and Robert Carlson, MD, of MaineHealth; Sterling Bennett, MD, MS, of Intermountain; John Carey, MD, of Henry Ford; and Pamela Murphy, PhD, APRN, of MUSC Health.

The Compass Group is an organization of not-for-profit IDN system lab leaders who collaborate to identify and share best practices and strategies. (For our coverage of their first call with CAP TODAY, see “Compass points chart the pandemic,” September 2020.) Here is what they told us on Sept. 1.

Greg Sossaman, what is the situation in New Orleans? Where is the public testing demand coming from, and how has it changed over the past month or so?
Gregory Sossaman, MD, system chairman and service line leader, pathology and laboratory medicine, Ochsner Health: The pediatrics group developed a whole service line around contracts and services they could provide to schools in the area. Testing could be part of that. We don’t have the capacity now from a PCR perspective, but we’re looking at that as we expand. We’re also looking at providing more rapid testing to employers. People understand the importance of rapid testing and that a test for which it takes a week to get the results isn’t helpful. So there’s been a push for rapid testing, and we’re working on that.

Susan Fuhrman, do you think that the news about Abbott getting approval for its rapid test and the demand for it are making a difference in your life or in the perception of the clinicians and the people in the laboratories?
Susan Fuhrman, MD, president, CORPath, Department of Pathology and Laboratories, OhioHealth Riverside Methodist Hospital, Columbus: The main thing to know is why you’re doing the test and what you will do with the result. That is something we as pathologists have known forever. If you’re testing people to see if they’re contagious today, that’s different from testing someone on whom a procedure will be done. They’re both asymptomatic but it’s different. For the asymptomatic person you’re going to take to the operating room, you want to be sure they don’t have presymptomatic COVID, or even asymptomatic COVID that you then push into symptomatic COVID because of the procedure. That’s one asymptomatic group.

The other is the group that is asymp­tomatic and they’re going to quarantine regardless, so what are you going to do with those results? If you are going to actively contact trace, you want to find the infected contacts rapidly, but testing a contact too soon—within a day or two of exposure—will likely fail to detect virus. The reason you want to find infectious contacts rapidly is so their contacts can be identified and quarantined, and their contacts traced, and so on. These secondary and tertiary positive contacts are also quarantined and tested.

The third asymptomatic group are the folks who probably won’t quarantine unless you tell them they’re positive, so testing them is needed to convince them to quarantine. And then there’s another group for whom you’re going to get a snapshot in time if you test once—were they detectable by PCR or by antigen testing today? Unfortunately, that just tells us if they were infectious today. It doesn’t tell us if they will be tomorrow.

We know that the virus replicates so fast that if you’re positive but below the limit of detection today by an antigen test, the chances are pretty good you will be positive by an antigen test tomorrow. So if you’re going to test people every day or every other day, then using a rapid antigen test is great for seeing if someone is infectious and, if so, quarantining them. Since no negative test is perfect at ruling out infectivity, a negative test does not mean you can throw away your mask and stop social distancing.

I am pleased that the CDC recently published on its website the recommendation that it is unnecessary to retest a positive patient within three months of being positive. I don’t know if that’s going to change with some of the questions about reinfection, but it will reduce unnecessary retesting of those who were recently positive.

We use the Abbott ID Now for our symptomatic patients in our urgent cares and our emergency rooms and freestanding emergency centers because those doctors want a result right away. The central laboratory is performing PCR testing on our asymp­tomatic patients. For our sympto­matic outpatients we mainly use the Abbott Now, depending on volume and availability of reagent for the Abbott assay and for the PCR assays. It’s a juggling act.

Stan Schofield, for this application of rapid tests to, say, junior high school students, how much explanation would you need to provide to the relevant authorities—both medical and in the schools—to get them to understand what the rapid test can do for that population and what it cannot do?

Stan Schofield, president, NorDx, and senior VP, MaineHealth: When I talk to private schools, universities, and colleges, I explain we are testing all of them but we are not doing antigen testing. We’re still with the gold standard, PCR. We’re at Bowdoin College today for 400 students getting swabbed. The Abbott card is made one mile from my office; we inspected their development lab for safety issues in May. It’s all first class. We can’t get a hand on one. The government bought them all, so we don’t know if it’s more sensitive than ID Now. We’re hearing it’s less sensitive, which would make sense given the price point, ease of use, and lack of sophistication without instrument interpretation, but we can’t prove that.

I tell people if you’re going to do these rapid tests you have to do them along the lines of this kind of mentality: Do you want five percent of the population tested with 99 percent accuracy, or do you want 95 percent of the population tested at 85 to 90 percent accuracy and with greater frequency and at lower cost? The rapid tests are a better way to capture pandemic population exposure and incidence rates. But we can’t use that in our facilities because we have to have a COVID-free environment for the surgical cases and diagnostic procedures and nothing less than PCR is acceptable.

The secondary issue is the demand. People have heard incredible stories about antigen testing. We have now started testing in the state of New Hampshire—a state contract for assisted-living facilities that required PCR. They won’t consider antigen testing in the nursing homes for asymptomatic patients.

Will something come close to the gold standard PCR, to maybe a level of being standard silver, good enough with better technology or better cards than what we have today? Yes, there’s a half-dozen companies—I’ve been talking to some—coming out with much lower-cost PCR, and they’ll probably be available by year end.

So there’s going to be more competition and we’ll be looking at that for more point-of-care PCR-level quality in our various organizations. But the FDA is taking a much harder stance on EUA.

The other point-of-care instruments that are coming out are expected this fall, and we’ll have to see what happens to the price point. If you can get an antigen test for $5 that’s 85 percent, would you pay $12 and get PCR at 98? I don’t know.

How is your supply of test kits for your PCR platforms?
Stan Schofield (MaineHealth): We’re using an LDT, so we have been stockpiling master mix and extraction kits. You would think it was Christmas last week when 75,000 pipette tips showed up here finally. At the same time, this week we went back to the gray market for 50,000 universal transport media and swabs out of South Korea. We had nine pallets delivered this week, and two weeks ago we had another nine, so we’re working hard to build up inventory to support our external community and corporate testing. There’s a lot of money there and we’re going to try to capture it while the sun’s shining.

Lauren Anthony, can you give us your reaction to what you’ve heard so far? I’m wondering about the new areas for test demand from businesses and schools and how you’re triaging the different test technologies as you reply to these questions and demands for testing.
Lauren Anthony, MD, system laboratory medical director, Allina Health, Minneapolis: We’re still extremely limited in what we can do on site. We have five platforms going for a total of 220 tests. That’s all we’re doing in-house. We’re collecting more than 2,000 a day and sending the vast majority out. So we’re focusing on trying to add more platforms to get more capacity.

We don’t have funding to stock up. We’re running lean, and we’re having to struggle to bring our case forward to get more equipment and further expand our platforms. We’re still low incidence in Minnesota. [On Oct. 19 the positive rate in the Twin Cities for all tests was six percent.]

We see the antigen test as a way to potentially cut down on PCR in the outpatient world if we can start detecting positives that don’t need PCR, but we’re not sure because it’s going to cost a lot to stock up on that. We’re wondering how others are able to stock up because we’re not. We’re very lean. We can’t bring in molecular platforms that are going to require additional staff to do the pipetting and extractions in a live environment. We’re looking at platforms that aren’t going to require adding staff, and it’s a challenge.

That’s interesting because COVID has been pretty magical for many labs with their administrations in terms of getting what they want and need.
Heather Dawson, VP of laboratory services, Allina Health, Minneapolis: The vendor we used pre-COVID didn’t come through, and when it did, the shipment arrived without COVID reagents. It came with only the STI testing we had originally intended. So with a very small molecular testing department and our recovery work focused on no additional FTEs, it’s been interesting to prove, especially with the large portion of inpatient testing that needs to be done, a return on the cost of all of this. We’re getting there but it’s slow. Because Mayo Clinic is down the road, people expect that we should use Mayo, but from a cost perspective that doesn’t always pan out.

Sarah Province, what’s going on in your neck of the woods?
Sarah Province, director of laboratory operations, AdventHealth, Orlando, Fla.: We are continuing to build capacity. We have consolidated most of the testing at our Orlando campus, and we have capacity now to run about 650 tests a day. We’re using multiple platforms—Luminex, DiaSorin, GenMark, Roche. We’re validating the BD Max now and a second BioMérieux eMag and Luminex MagPix, and a second Eppendorf cycler. We have five Siemens PCR dual systems ready to install. So we’re building capacity. We have pooled testing available on our Luminex Aries.

Finding space for this equipment and the staff needed to run it are our biggest challenges. Our volume has fallen off in the past few weeks, but that is a bit encouraging because we will be better prepared for a surge with school starting and flu season.

We’ll also be able to bring in all of our sendout testing. We send out 200 to 500 samples a day to three different reference labs for ambulatory-type testing. We’ll be able to bring that in-house and all of our inpatient admission screening and any other testing we need the capacity for.

Julie Hess, executive director, laboratory services, Advent­Health, Orlando, Fla.: Our corporate leadership, which is based near the Orlando area, set up a lab governance early on, and they listened to us and the ROIs we presented on what our costs were to send samples out to reference labs and if we could bring them in-house.

We highlighted how patient management would be impacted if we could do these tests locally with a reasonable turnaround time. All of that helped to shape key initiatives by our organization. So they have invested a lot of money—more than $3 million—for us to be able to help manage this.

There has been a lot of aggressive work to get contracts signed and to get negotiated buying power. It has put a strain on our lab team, though, because we are struggling now with the staffing. We could do even more than we are now, but finding people who are qualified, because Florida has a state licensure requirement, is difficult.

We are focused on antigen testing for our community testing. We have a branch that is kind of separate from our laboratory, with our rapid care clinics, and it has embraced the antigen concept. They’re testing symptomatic patients in the community, primarily with the Quidel Sofia platform. We got our hands on the BD Veritor and reagents, and we began to do pilot studies with that.

No one on this call would be surprised to hear the sensitivity was significantly lower than for PCR. Our data seem to suggest that the patients in a rapid care or community clinic setting are going to their doctor within five days as it’s recommended by Quidel in its package insert. But by the time they get to a point where they want to go to an emergency department, they seem to be well past that, so we’re not picking them up as positive on our test.

We’ve talked a lot about what the CDC guidance is about antigen tests in terms of doing surveillance and monitoring a community or population and having that repeat test. We’re exploring what that could look like and if there’s value in it. It could be in our nursing homes as a general surveillance screen. It could be in some of our local prison populations or schools.

And there is also our own patient population. We have a process now for patients on infusion therapy or radiation oncology that they must be retested every 30 days. If we’re going to do frequent repeat testing on a population, even if they’re asymptomatic, I’m wondering if antigen testing would play a role there. I’m concerned about the sensitivity of antigen testing and what decisions we make—how we take care of the patients who are negative if there’s a chance they are positive. But considering the limitation of resources—of people and supplies for PCR—I don’t want to rule that out.

Jim Crawford, what would you say about taking care of this cohort of patients who are on infusion therapy and need to be tested? What strategies are you employing at Northwell?